LUT's that emulate the ACES workflow

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I’ve just updated the links in the original post to include a package of LUTs with a lower contrast than normal. 0.85 which is my personal favourite.

I’ve also updated the original package to correct some errors in the Canon 2020 varieties, so many possibilities, so little time :slight_smile:

Cheers

Geoff Boyle NSC

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The 0.85 contrast versions can be matched in Resolve or Baselight by applying 0.85 contrast, with the default pivot setting of 445 (or 0.435) in ACEScct. It can also be replicated with an ASC-CDL adjustment with Slope: 0.85 and Offset: 0.06525.

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I have tested a Teradek Bolt 3000 and an AJA LUT box today and added them to the list:

http://www.antlerpost.com/downloads/LUT_ranges.pdf

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And as a bonus freebie, here is a simple drag-and-drop Automator app for OS X which will convert a 33^3 LUT to 17^3 for LUT devices which require that:

http://www.antlerpost.com/downloads/resize_33_17.zip

It’s not a robust universal converter, so no guarantees it will work with other LUTs, but it works with my ACES sets.

The table is updated again to add IS Mini and ATOMOS. I am working on getting other devices to test. There is also a correction to the entry for FSI monitors, due to an earlier misunderstanding over terminology.

I don’t know if this has been mentioned here before but if not here it goes:

There is now a really easy way to emulate some ACES workflows using 3D LUTs exported from DaVinci Resolve.

As of the latest versions of Resolve (15.2.2 I think but could be earlier), DaVinci’s own ACES Transform OFX Plugins as well as their Colour Space Transform Plugins can now be exported into 3D LUTs (previously they couldn’t).

If you set your Colour Management to DaVinci YRGB and on any given clip create two serial nodes with the new ACES Transform OFX plugin on each you can emulate most ACES IDT+RRT+ODT combinations and then export a 3D LUT out of them using the “Generate 3D LUT (CUBE)” command.

Basically the first node works to select the IDT and the ACES working Space and the second node works for coming from the ACES working space to the selected ODT.

If you wanted to create an ACES emulation LUT for the Alexa IDT using ACES Rec709 ODT to monitor on set for example you could easily:

Set an ACES Transform OFX plugin on the first serial node, set the ACES version to say 1.1, then on Input Transform select Alexa, on Output Transform Select say ACEScct. On the second serial node you would then chose ACEScct as the Input Transform and the “Rec709 as the output transform.

All that is left to do is right click on the clip thumbnail and select “Generate 3D LUT (CUBE)” and voila, you have a 3D LUT that combines the IDT, RRT and ODT.

As far as I know, this method will only export LUTs in Extended Range levels (Full Range). There may be a workaround to export Legal Range level LUTs in Resolve but I’m not aware of it. You could always use a tool like Lattice if you need to convert from extended to Legal range but otherwise this method seems to work wonders and it’s accessible to anyone with a copy of Resolve Studio.

Just as a side note, you can obviously put however many nodes with primary corrections between the two ACES transform nodes to export a LUT with a baked in look that goes farther than the ACES IDT+RRT+ODT transforms.

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I’ve been experimenting with this approach and it seems to work well.

I’ve added a new ACES LUT page to CML that has LUT’s generated this way for Alexa, BMD, Canon, Varicam & Venice.

They come in 2 flavours, LowCon as before, Basic again as before and a new “Kodak” version where I have tweaked the image so that the black, grey, white patches on the Kodak Grey Scale Plus card match the levels printed on the back of the chart. It’s an increased contrast from 1 to roughly 1.12.
https://cmltests.net/ACES-LUTS.html

Can these LUTs be used on the camera to emulate ACES

Can these LUTs be used on the camera (arri alexa) to emulate ACES ie. without using a LUT box?
Thanks
Michael

You’ll need to use ARRI software that is downloadable from arri.com to convert them to the arri look format but then yes, you can :slight_smile:

I’ve converted the Sony and Panasonic already, I guess I’ll have to add the ARRI ones :slight_smile:
These are the original ones https://www.cinematography.net/ACES-LUT’s-for-use-in-a-non-ACES-environment.html
I added these ones later https://cmltests.net/ACES-LUTS.html
I’ll try converting some of the ARRI ones to arri look format by this time next week.

Great thanks for sending through. All looking positive!

Another query I had was on the livegrade system using BoxIO for the IDT and ODT from the arri log c, the frame overlays like the red REC turns orange. Is this to do with the IDT and ODT?

Thanks
M

That’s right. The saturated red of the REC overlay is not a colour that would ever appear in a normal LogC / AWG image. And passing it through a process intended for LogC /AWG gives that result.

Hmm, I don’t have an Alexa to check on and I’m not happy with what I’m seeing in the ARRI look tool.
There seems to be a legal/data issue.
I’ve checked the BMD ones loaded into a LUT box and they work fine (I have a G1 and a G2 here at the moment)
It’s just the conversion to ARRI camera format that seems an issue, I’m doing that with Lattice.
I’ll have another go later but it’s a pain that it only works on a Mac.

Once again Nick Shaw has come to the rescue :slight_smile:
I’ve uploaded a revised page that now include .aml look files for Alexa
https://cmltests.net/ACES-LUTS.html

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Just to check Mr. Boyle, the ARRI LUTs includes the video to full conversion?
This is because LogC in signals are Video Legal only and IDT expect full?
So, if you are working with regular IDTs inside Resolve or another system, all Alexa clips must be interpreted as Video Data Levels? (to perform the right contrast expansion, since IDT is Full but LogC uses just legal range)
Other IDTs expects full range and to define Full Data Levels is the correct way (and inside the LUT the fix was not necessary)
Thanks for help me to understand better.

@ediwalger, you make an important point about being aware of the differences in range scaling between different log signals over SDI and e.g in Resolve.

@cmlgeoff will have to answer as to what he has done with the latest round of LUTs, but I can confirm that when I made the set of LUTs linked in the first post on this thread I took account of the differences in data range of the various log formats “on the wire”. And as described in the first post, the LUTs are each created in two versions, one (EE) for LUT devices which perform a legal to full scale before applying the LUT and a full to legal scale afterwards, and another (LL) for LUT devices which apply the LUT directly to the unscaled incoming SDI code values and also send the LUT output unscaled to their SDI output. And the table I posted shows which version should be used in various LUT boxes.

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Your review of LUT Hardware is very welcomed, thank you again! Do you confirm that the Prores clips made from ARRI cameras all are video range? (And must be interpreted as video data levels in resolve and in other sytems too). Is this the only exception about Log, and the rest of manufacturers writes full range in each propietary Log encodings? Thanks in advance Nick Shaw.

Sadly it’s not that simple!

ProRes recordings from ARRI, RED and Blackmagic cameras all map their log curves to “video” range, as do their SDI outputs. This means they need to be interpreted as “Video” in Resolve. Many other systems include a “hidden” legal to full scale in their ProRes decodes, so you need to verify the behaviour. Baselight’s handling of ProRes has varied with different versions. Currently Baselight 5.2 decodes ProRes to legal range (un-scaled normalised code values) but adds a legal to full scaler to the input layer, which you have the option to switch off.

Canon, Panasonic and Sony cameras scale their baked video recordings to “video” range, but do not scale their log recordings.

Thus to get a match in Resolve between a ProRes recording from an ARRI, Blackmagic or RED camera and a Raw recording you can leave the Clip Attributes set to the default Auto, which for ProRes is “Video”. For Canon, Panasonic and Sony ProRes recordings, the Clip Attributes need to be set to “Full” to match a Raw recording with log ProRes, but should be left on “Auto” or “Video” for a baked video recording.

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Thanks for clarify! Very useful information again.